Caffenol: The coolest B&W film developer you're not using

Caffenol:  def.  using instant coffee crystals along with other household items as a B&W film developer.

I am all for sticking it to the man.  Well at least when it comes to paying good money to large name brand companies for expensive film developers.  Caffenol is a concoction of instant coffee, vitamin C and washing soda.  All of these items can be bought at stores other than camera and photo shops, usually at a grocery store or big box store.

Not only does instant coffee work as a B&W film developer, it works amazingly well.  I have shot many rolls of film and tested out Caffenol developer mixtures and I have come up with a formula combination that I believe rivals any commercially available film developer.  Caffenol is extremely compensating. The highlight development exhausts while shadow development continues giving a nice full range of tonal values.  The negatives are sharp and have a slight stain.

There is a lot of information about Caffenol online. I will provide the details of my recipe and workflow.  The results are simply stunning!  Here is the ingredient list:

• Instant coffee ( I have used Trader Joes, Folgers and most grocery store brands)
• Vitamin C (ascorbic acid) powder
• Washing Soda (Arm and Hammer) in the laundry detergent aisle.  It's in a big yellow box
• Potassium Bromide (not required, but certainly nice to have)

After I realized that Caffenol works, I had to know why.  I had to know the science behind it.  Here it is.

Washing soda is really sodium carbonate.  This is actually a common component of many film developers. This is know as the accelerator or alkali, as it provides an alkaline environment conducive to the silver reduction process.  Other accelerators used in commerical film developers are sodium hydroxide (red devil lye) and Borax (yep, 20 Mule Team Borax also available in most grocery stores)

The developing agent is a combination of caffeic acid from the Instant coffee and the Vitamin C. These two combined create a super-additive chemical that reduces the silver halide in the film to silver metal.  Other common developing agents used in commerical film developers are Metol, Phenidone, and Hydroquinone, none of which are available in your local grocery store!

I purchase Vitamin C from ebay.  You can find many suppliers of powdered Vitamin C.  I purchased 250 grams for around $8.50 including shipping.  Only 5 grams of Vitamin C is used per batch of Caffenol.

Finally, potassium bromide.  This is an optional ingredient, and one you won't find in the grocery.  I purchase it online from Photo Formulary, available through Adorama.

Potassium bromide is a restrainer.  This holds back overall development.  The reason I use this?  My Caffenol workflow development is for a 60 minute semi-stand development (more on this in a bit) and the longer the film is "exposed" to the developer the greater the possibility of chemical fogging.  In other words, silver grains not exposed in the camera will darken from prolonged exposure to developing agents creating a fog or dark haze on the film.  Potassium bromide will reduce the fog by holding back development. This also will tend to increase the contrast a tad as the shadows in the film will show less development than the highlights.  The potassium bromide is used sparingly, only about 2.5mm per roll of film.  I buy it in crystal form and weight 20 grams on a digital scale and dissolve it in 200 milliliters on warm water.  10 milliliters of this solution will equal 1 gram of potassium bromide.

I purchased an inexpensive digital scale from ebay.  I use coffee filters to measure out the ingredients.

I start with 400 ml of water at 68 degrees

add:  8 grams of washing soda.  dissolve completely
add:  5 grams of Vitamin C.  dissolve and wait for bubbles to form on the bottom of mixing vessel.  Stir until bubbles disappear.
add:  20 grams of  instant coffee.  mix well and let stand for 5 minutes to settle.
add:  2.5ml of potassium bromide (if using and not required)
add water to make 500 ml total.

Develop your film normally for 60 minutes in Caffenol.  Using a semi-stand development technique you will agitate the film continuously for 1 minute and then again for 10 seconds at the 2. 4, 8, 16, and 32 minute marks. The remainder of the time the film will sit untouched until the 60 minute time is up. Discard the Caffenol as it is a one-time use developer. Do not reuse.

Stop the development using running water only. Do not use an acid stop bath.  Acid stop when used with a developer containing sodium carbonate (washing soda) can cause carbon dioxide gas to release which can cause blistering on the film)  Rinse film for 30 seconds in running water at 68 degrees

Fix the film normally and then wash and photo flo normally as well.

I found the semi-stand agitation and recipe work well with Kodak TMAX 400 generation 2 and Fuji Acros 100.

I shot several test frames of a Macbeth Color Checker at several ASA settings to see which setting would give me the best exposure with Caffenol.  This test revealed Kodak Tri-X 400 was best exposed at 400.

This is Kodak TMY-2:  TMAX 400 Generation 2 processed for 60 minutes using above recipe

This is Eastman 5222 Double-X cinema film exposed at ASA 200 and processed in Caffenol